<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .a .b .c{

    }
    .c{
      
    }
  </style>
</head>
<body>
  <div id="app">
    <div class="name">Tom</div>
    <div class="age">18</div>
  </div>

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      tag: 'div',
      id: 'app',
      class: '',
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          class: 'name',
          text: 'Tom',
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          class: 'age',
          text: '18',
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</body>
</html>